共查询到20条相似文献,搜索用时 15 毫秒
1.
M. A. Ivanov G. S. Ludva A. V. Mukovnya S. N. Kochetkov V. L. Tunitskaya L. A. Alexandrova 《Russian Journal of Bioorganic Chemistry》2010,36(4):488-496
4′-Fluoro-2′,3′-O-isopropylidenecytidine was synthesized by the treatment of 5′-O-acetyl-4′-fluoro-2′,3′-O-isopropylideneuridine with triazole and 4-chlorophenyl dichlorophosphate followed by ammonolysis. The interaction of 4′-fluoro-2′,3′-O-isopropylidenecytidine with hydroxylamine resulted in 4′-fluoro-2′,3′-O-isopropylidene-5′-O-acetyl-N
4-hydroxycytidine. The removal of the 2′,3′-O-isopropylidene groups led to acetyl derivatives of 4′-fluorouridine, 4′-fluorocytidine, and 4′-fluoro-N
4-hydroxycytidine. 4′-Fluorouridine 5′-O-triphosphate was obtained in three steps starting from 4′-fluoro-2′,3′-O-isopropylideneuridine. 4′-Fluorouridine 5′-O-triphosphate was shown to be an effective inhibitor of HCV RNA-dependent RNA polymerase and a substrate for the NTPase reaction
catalyzed by the HCV NS3 protein, the hydrolysis rate being similar to that of ATP. It could also activate a helicase reaction
with an efficacy of only threefold lower than that for ATP. 相似文献
2.
Deoxysugar, 2′, 3′, 4′-tri-O-methylrhamnose is an essential structural component of spinosyn A and D, which are the active ingredients of the commercial
insect control agent, Spinosad. The spnH gene, which was previously assigned as a rhamnose O-methyltransferase based on gene sequence homology, was cloned from the
wild-type Saccharopolyspora spinosa and from a spinosyn K-producing mutant that was defective in the 4′-O-methylation of 2′, 3′-tri-O-methylrhamnose. DNA sequencing confirmed a mutation resulting in an amino acid substitution of G-165 to A-165 in the rhamnosyl
4′-O-methyltransferase of the mutant strain, and the subsequent sequence analysis showed that the mutation occurred in a highly
conserved region of the translated amino acid sequence. Both spnH and the gene defective in 4′-O-methylation activity (spnH165A) were expressed heterologously in E. coli and were then purified to homogeneity using a His-tag affinity column. Substrate bioconversion studies showed that the enzyme
encoded by spnH, but not spnH165A, could utilize spinosyn K as a substrate. When the wild-type spnH gene was transformed into the spinosyn K-producing mutant, spinosyn A production was restored. These results establish that
the enzyme encoded by the spnH gene in wild-type S. spinosa is a rhamnosyl 4′-O-methyltransferase that is responsible for the final rhamnosyl methylation step in the biosynthesis of spinosyn A. 相似文献
3.
A. M. Varizhuk S. V. Kochetkova N. A. Kolganova E. N. Timofeev V. L. Florent’ev 《Russian Journal of Bioorganic Chemistry》2010,36(2):199-206
A dinucleotide containing a C3′-NH-C(O)-CH2-C5′ amide internucleotide bond was synthesized by the interaction of 3′-deoxy-3′-amino-5′-O-(tert-butyldimethylsilyl)thymidine with 3′-O-benzyl-2′-O-tert-butyldimethylsilyl-5′-deoxy-5′-carboxymethylribosylthymine, which was obtained from 2′-O-acetyl-3′-O-benzyl-5′-deoxy-5′-ethoxycarbonylmethylribosylthymine through the methanolysis of the acetyl group followed by silylation
of liberated hydroxyl and ester saponification. After standard manipulation with protecting groups, the dinucleotide was converted
into 3′-O(2-cyanoethyl-N,N-diisopropylphosphoramidite), which was used for the synthesis of modified oligonucleotides on an automated synthesizer. The
melting curves of the duplexes formed by modified and complementary natural oligonucleotides were registered, and the melting
temperatures and thermodynamic parameters of the duplex formation were calculated. The introduction of a single modified bond
into the oligonucleotide led to an insignificant decrease in the melting temperature of these duplexes as compared to unmodified
ones. 相似文献
4.
E. A. Yelin V. V. Onoprienko I. A. Kudelina A. I. Miroshnikov 《Russian Journal of Bioorganic Chemistry》2000,26(8):774-783
Starting from the previously describedtert-butyl esters of 4-epimericN-benzyloxycarbonyl-4-hydroxyprolines andN-benzyloxycarbonyl-4-trans- and 4-cis-trifluoroacetaminoprolinetert-butyl esters, the corresponding uprotected 4-aminoprolines and a number of their partially protected derivatives were synthesized
via the intermediate 4-O-mesyl and 4-azide derivatives. The reductive amination ofN-benzyloxycarbonyl-4-oxoprolinetert-butyl ester with ammonium acetate led toN-benzyloxycarbonyl-4-cis-4′-cis- and 4-cis-4′-trans-diprolinylamines. The1H NMR and CD spectra of the synthesized compounds are described. 相似文献
5.
Glomus intraradices , Glomus mosseae, and Gigaspora rosea leads to the accumulation of cyclohexenone derivatives. Mycorrhizal roots of all plants accumulate in response to all three
fungi blumenin [9-O-(2′-O-glucuronosyl)-β-glucopyranoside of 6-(3-hydroxybutyl)-1,1,5-trimethyl-4-cyclohexen-3-one], 13-carboxyblumenol C 9-O-gentiobioside, nicoblumin [9-O-(6′-O-β-glucopyranosyl)-β-glucopyranoside of 13-hydroxy-6-(3-hydroxybutyl)-1,1,5-trimethyl-4-cyclohexen-3-one] and another, as yet unidentified, cyclohexenone
derivative. The accumulation of all four compounds in three tested mycorrhizal plants colonized by the three arbuscular mycorrhizal
fungi indicates no fungus-specific induction of these compounds.
Accepted: 6 October 1999 相似文献
6.
A UDP-glucose: anthocyanin 3′,5′-O-glucosyltransferase (UA3′5′GT) (EC 2.4.1.-) was purified from the petals of Clitoria ternatea L. (Phaseoleae), which accumulate polyacylated anthocyanins named ternatins. In the biosynthesis of ternatins, delphinidin
3-O-(6″-O-malonyl)-β-glucoside (1) is first converted to delphinidin 3-O-(6″-O-malonyl)-β-glucoside-3′-O-β-glucoside (2). Then 2 is converted to ternatin C5 (3), which is delphinidin 3-O-(6″-O-malonyl)-β-glucoside-3′,5′-di-O-β-glucoside. UA3′5′GT is responsible for these two steps by transferring two glucosyl groups in a stepwise manner. Its substrate
specificity revealed the regioselectivity to the anthocyanin′s 3′- or 5′-OH groups. Its kinetic properties showed comparable
k
cat values for 1 and 2, suggesting the subequality of these anthocyanins as substrates. However, the apparent K
m value for 1 (3.89 × 10−5 M), which is lower than that for 2 (1.38 × 10−4 M), renders the k
cat/K
m value for 1 smaller, making 1 catalytically more efficient than 2. Although the apparent K
m value for UDP-glucose (6.18 × 10−3 M) with saturated 2 is larger than that for UDP-glucose (1.49 × 10−3 M) with saturated 1, the k
cat values are almost the same, suggesting the UDP-glucose binding inhibition by 2 as a product. UA3′5′GT turns the product 2 into a substrate possibly by reversing the B-ring of 2 along the C2-C1′ single bond axis so that the 5′-OH group of 2 can point toward the catalytic center.
K. Kogawa, N. Kato, K. Kazuma, and N. Noda contributed equally to this work. 相似文献
7.
Previous studies on the lipase-mediated acylation of 6-azauridine with vinyl stearate in organic solvents revealed that while
preparing a potential prodrug, 3′-O-stearoyl-6-azauridine, a lipase from Burkholderia cepacia showed high regioselectivity toward the second hydroxyl group. The most suitable reaction solvent, molar ratio of vinyl stearate
to 6-azauridine, and reaction temperature were anhydrous acetone, 15:1, and 45°C, respectively. Under these conditions, the
initial reaction rate, 3′-regioselectivity, and maximum substrate conversion were as high as 10.4 mM/h, 86.0, and 99.0%, respectively. 相似文献
8.
Arvind Misra Pratibha Dwivedi Mohammad Shahid 《Russian Journal of Bioorganic Chemistry》2009,35(1):62-67
A modified fluorescent probe UFAA AAT CTC CGC CGC was synthesized using the nucleoside analogue 3′-O-(N,N′-diisopropylamino-2-cyanoethoxyphosphinyl)-5′-O-(4,4′-dimethoxytrityl)-2′-O-(dansyl-1-sulfonamidohexylaminocarbonyl)uridine for hybridization studies with perfectly matched (U/A) complementary DNA
and with a DNA strand having similar G-rich telomeric units at their 3′-ends. Data on the thermal stability and decrease in
fluorescence intensity due to the presence of dG units clearly demonstrated the potential application of this approach in
DNA diagnostics in homogeneous hybridization assays.
The text was submitted by the authors in English. 相似文献
9.
Mannosylerythritol lipids (MELs) are glycolipid biosurfactants produced by Pseudozyma yeasts. They show not only the excellent interfacial properties but also versatile biochemical actions. In the course of
MEL production from soybean oil by P. antarctica and P. rugulosa, some new extracellular glycolipids (more hydrophobic than the previously reported di-acylated MELs) were found in the culture
medium. The most hydrophobic one was identified as 1-O-alka(e)noyl-4-O-[(4′,6′-di-O-acetyl-2′,3′-di-O-alka(e)noyl)-β-d-mannopyranosyl]-d-erythritol, namely tri-acylated MEL. Others were tri-acylated MELs bearing only one acetyl group. The tri-acylated MEL could
be prepared by the lipase-catalyzed esterification of a di-acylated MEL with oleic acid implying that the new glycolipids
are synthesized from di-acylated MELs in the culture medium containing the residual fatty acids. 相似文献
10.
Wiesława Bylka 《Acta Physiologiae Plantarum》2004,26(4):393-398
A new acetylated flavonol glycoside: patuletin 3-O-[5′″-O-feruloyl-β-D-apiofuransyl (1′″→2′′)-β-D-glucopyranoside] (2), together with a known patuletin 3-O-β-D-glucopyranoside (1) were isolated from the aerial part of Artiplex littoralis L. (Chenopodiacease). Their structures were elcidated by acid hydrolysis and spectroscopic methods including UV, 1H, 13C NMR and ESI-MS for both compounds, additionally 2D-NMR, HSQC, HMBC experiments were performed for 2. 相似文献
11.
A. M. Varizhuk S. V. Kochetkova N. A. Kolganova E. N. Timofeev V. L. Florent’ev 《Russian Journal of Bioorganic Chemistry》2009,35(5):585-591
A method for the synthesis of 5′-deoxy-5′-ethoxycarbonylmethyl nucleosides has been developed. 3-O-benzyloxymethyl-1,2-O-isopropylidene-α-D-allofuranose was oxidized by sodium periodate to form a 5′-aldo derivative, which was converted by the reaction with triethylphosphonoacetate
in the presence of sodium hydride into a 5-deoxy-5-ethoxycarbonylmethylene derivative. The hydration of the unsaturated compound
gave 5-deoxy-5-ethoxycarbonylmethyl-1,2-O-isopropylidene-α-D-ribofuranose. After the benzylation of 3-hydroxyl, the removal of the isopropylidene group by heating with acetic acid, and
the subsequent acetylation, 1,2-di-O-acetyl-3-O-benzyl-5-deoxy-5-ethoxycarbonylmethyl-D-ribofuranose was obtained, which reacted with persilylated nucleic acid bases to form 5′-deoxy-5′-ethoxycarbonylmethyl nucleosides. 相似文献
12.
The lipophilicity of kojic acid [5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one] was improved by esterifying kojic acid with either divinyl adipate, vinyl hexanoate, vinyl octanoate or vinyl decanoate using protease from Bacillus subtilis for 7 d. 1H-NMR and 13C-NMR showed that the primary hydroxyl group at the C-7 position of kojic acid was regioselectively esterified to afford 7-O-vinyl adipoyl kojic acid, 7-O-hexanoyl kojic acid, 7-O-octanoyl kojic acid and 7-O-decanoyl kojic acid (13–27% yield). The kojic acid esters had radical scavenging activities, inhibited tyrosinase activity and was biodegradable. 相似文献
13.
This work was to characterize the generation of nitric oxide (NO) in Taxus yunnanensis cells induced by a fungal-derived cerebroside and the signal role of NO in the elicitation of plant defense responses and
taxol production. (2S,2′R,3R,3′E,4E,8E)-1-O-β-d-glucopyranosyl-2-N-(2′-hydroxy-3′-octadecenoyl)-3-hydroxy-9-methyl-4,8-sphingadienine at 10 μg/ml induced a rapid and dose-dependent NO production
in the Taxus cell culture, reaching a maximum within 5 h of the treatment. The NO donor sodium nitroprusside (SNP) potentiated cerebroside-induced
H2O2 production and cell death. Inhibition of nitric oxide synthase activity by phenylene-1,3-bis(ethane-2-isothiourea) dihydrobromide
or scavenging NO by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide partially blocked the cerebroside-induced
H2O2 production and cell death. Moreover, NO enhanced cerebroside-induced activation of phenylalanine ammonium-lyase and accumulation
of taxol in cell cultures. These results are suggestive of a role for NO as a new signal component for activating the cerebroside-induced
defense responses and secondary metabolism activities of plant cells.
Taxol is a trademark of Bristol-Myers Squibb, Madison, NJ. 相似文献
14.
Kunijiro Yoshitama Tomoyuki Kawasoe Nariyuki Ishikura 《Journal of plant research》1993,106(3):223-227
From the blue seed coats ofOphiopogon jaburan, a new flavonol glycoside was isolated as needles and determined to be kaempferol 3-O-β-d-galactoside-4′-O-β-d-glucoside (OK-2) by UV and NMR spectral analyses. OK-2 and kaempfrol 3, 4′-di-O-β-d-glucoside (OK-1), which was detected previously, in the blue seed coat were present in a molar ratio of about 13:7. OK-2
was newly found as a factor causing the blueing effects on ophionin which is a main anthocyanin in the blue seed coats. The
mixture of 4.8×10−3 M OK-2 and 2.5×10−3 M ophionin in Mcllvaine's buffer solution (pH 5.6) showed stable blue color, and the absorption spectrum of the mixture showed
two absorption peaks and a shoulder in visible reasion, coinciding with that of the fresh blue seed coat. The effect of ophionin
and OK-2 co-pigmentation on the blue color of seed coat ofO. jaburan was discussed. 相似文献
15.
3-O-Rhamnopyranosylisorhamnetin, 3-O-glucopyranosylisorhamnetin, 7-O-galactopyranosylluteolin, quercitrin, isoquercitrin, wistin, and a novel isoflavonoid, 3′-hydroxy-6,4′-dimethoxy-7-O-β-D-glucopyranosylisoflavone, were isolated from the aerial parts ofaragana alaica. Of these, the previously described compounds were identified on the basis of their physicochemical and spectral characteristics,
whereas the spectral analysis and conversion to a known compound, cladrastin, allowed the structural elucidation of the novel
isoflavone glycoside. 相似文献
16.
A. V. Aralov V. N. Klykov O. G. Chakhmakhcheva V. A. Efimov 《Russian Journal of Bioorganic Chemistry》2011,37(5):586-592
A general scheme for the synthesis of ribonucleotides containing an alkoxymethyl group at the 2′-O-position of ribose and an O-nucleophilic catalytic 4-methoxy-1-oxido-2-picolyl phosphate-protecting group has been developed for the introduction into
oligonucleotides during their solid-phase synthesis by the phosphotriester method. The scheme has been tested in the synthesis
of monomers with 2′-O-modifying groups as examples: 2-azidoethoxymethyl, propargyloxymethyl, and 3,4-cyclocarbonatebutoxymethyl groups. 相似文献
17.
Flavonoid profiles of 132 populations (472 individuals) ofAsplenium normale, and related species,A. boreale, A. shimurae, andA. oligophlebium var.oligophlebium and var.iezimaense in Japan were surveyed by HPLC and 2D-PC. Of the five taxa, each ofAsplenium boreale, A. shimurae andA. oligophlebium including var.iezimaense had consistent flavonoid composition: apigenin 7, 4′-di-O-rhamnoside (9) inAsplenium boreale, 7-O-glucosyirhamnosides of apigenin and luteolin (6 and 7) inA. shimurae and genkwanin 4′-O-glucosyl-rhamnoside (5) in twoA. oligophlebium varieties. On the other hand,Asplenium normale was divided into seven chemotypes A-G: A-type has 7-O-dirhamnosides of apigenin and luteolin (1 and 2) and genkwanin 4′-O-glucosylrhamnoside (5); B-type, 5 alone; C-type, apigenin 7-O-rhamnoside-4′-O-glucosylrhamnoside (8); D-type, 1 and 2; E-type, 1,2 and 8; F-type, 1, 2, 5 and 8; and G-type, 5 and 8. Among them, the most
frequent types were A, B and C, and A-type was mainly distributed in inland of Honshu, Shikoku and Kyushu, while B- and C-types
extended their distribution areas southwards in general and occur along the Pacific coast with several exception. Chemical
and evolutionary relationships amongAsplenium boreale, A. shimurae, A. oligophlebium, and the chemotypes ofA. normale were discussed on the basis of general biosynthetic pathway. 相似文献
18.
The structure of the sulfated analogue of cauloside C, a biologically active triterpenoid glycoside, was elucidated to be
3-O-[β-D-glucopyranosyl-(1→2)-α-L-arabinopyranosyl]-hederagenin 23,4′,4″,6″-tetrasulfate pentasodium salt by the comparison of its13C NMR spectrum with that of cauloside C potassium salt. 相似文献
19.
Marek Doskocz Agnieszka Strupińska Szczepan Roszak Monika Prokopowicz Leo H. Koole Paweł Kafarski 《Journal of molecular modeling》2009,15(6):651-658
The study of spin-spin coupling constants across hydrogen bond provides useful information about configuration of complexes.
The interesting case of such interactions was observed as a coupling across an intramolecular hydrogen bond in 8-bromo-2′,3′-O-isopropylideneadenosine between the -CH2OH (at 5″ proton) group and the nitrogen atom of adenine. In this paper we report theoretical investigations on the 4h
J
NH coupling across the H″-C-O-H···N hydrogen bond in adenosine derivatives in various solvent models.
Figure Coupling constants in 8-bromo-2′,3′-O-isopropylideneadenosine
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
20.
Production of the benzophenanthridine alkaloids in Eschscholtzia californica suspension cell cultures was optimized by adding 0.5 mg methyl jasmonate (MJ) and 0.02 mg salicylic acid (SA)/g FCW after
7 days cultivation. Sanguinarine reached 24 mg/g DCW by such treatment; 10 times higher than in control cell cultures. MJ
and SA induced expression of berberine bridge enzyme and 3′-hydroxy-(S)-N-methylcoclaurine-4′-O-methyltransferase, respectively. MJ plus SA induced over-expression of both enzymes. 相似文献